I want to point out an important detail about the interactive detail in spoken communication called gaze.
Gaze is the pattern of 1) when an individual makes eye contact with the person or group she is communicating with, coupled with 2) when she drops her eye contact. Different cultures have different patterns; there are gender differences as well.
Gaze choices are almost always subconscious behavior patterns. To make a change you need to be aware of your idiosyncratic patterns. For example many people look up and to the left when they are thinking; many people drop eye contact when they are being reprimanded; etc.
Many of us make eye contact when we are speaking to someone, and drop eye contact when the person responds.
My recommendation is that you maintain natural eye contact when you are speaking, and then maintain the same eye contact when the other person speaks and you are the listener.
By breaking eye contact after you speak, you are sending a signal that 1) you are not interested in what the person has to say, 2) you do not respect the person, 3) you have disconnected from the context completely.
Gaze — as with communication details — has to do with the listener’s perception of your intent. Your actual intent may not match the perception — so it is best to remove all of the “noise” from your communication choices and behavior.
You can practice playing with your gaze choices. Have fun!